(Not Applicable)
(Not Applicable)
The present invention relates generally to fluid valves, and more particularly to a distribution diaphragm valve as used in cooperation with a downstream purge valve.
A diaphragm type tee-valve includes a valve housing body which has a main flow channel formed through it. In this regard, the main flow channel is intended for unobtrusively forming an in-situ portion of the product distribution loop to which it is attached. The tee-valve may be utilized a point of use or distribution valve for receiving fluid product from the product distribution loop. A valve mounting surface formed upon the valve housing body. An upstream passage is formed to transversely extend from the main flow channel to the valve mounting surface. A downstream passage is formed to extend from the valve mounting surface and terminate at a distribution port. A valve weir separates the upstream and downstream passages adjacent the valve mounting surface. A diaphragm valve housing may be mounted upon the valve mounting surface, with a diaphragm being configured to engage the valve weir. As such, with the diaphragm in an open position, the downstream passage is in fluid communication with the upstream passage. for passage of fluid flow from the upstream distribution passage through the distribution port. Actuation of the diaphragm against the valve weir prevents fluid flow between the upstream and downstream passages thereby closing the valve.
As mentioned above, such tee-valves may be utilized as point of use or distribution valves for receiving fluid product from a product distribution loop. These valves have application in a wide range of fluid handling systems, such as those for pharmaceutical, biotech processing, food and beverage, and cosmetic and consumer products applications. Such applications are typically subject to strict governmental regulations and industry practices and procedures. Of particular concern is the cleanliness and sterility of the downstream passage after usage of the distribution valve. In this regard, a purge or cleaning operation of the downstream passage is desirable while the distribution valve is in the closed position. Pressurized fluid, steam or air is utilized for such purpose. A separate diaphragm type purge valve is used to introduce such pressurized fluid, steam or air to the downstream passage of the distribution valve.
Referring now to FIGS. 1 and 2, there is shown a exemplary prior art distribution valve and purge valve arrangement. FIG. 1 is a prior art distribution valve housing 10 which is connected to a product distribution loop 12. The distribution valve housing 10 is provided with an upstream passage 14, a downstream passage 16 and distribution valve weir 18 which separates the upstream and downstream passages 14, 16. The downstream passage 16 terminates at a distribution port 20.
A purge valve housing 22 is attached to the downstream passage 16 via a tubular fitting 24. The purge valve housing is of a diaphragm type and is provided with a purge valve weir 26. The purge valve housing 16 is used to introduce pressurized fluid, steam or air to the downstream passage 16 through the tubular fitting 24. FIG. 2 is a side view of the prior art distribution valve housing 10 and attached purge valve housing 16 (each with a diaphragm housing 28, 30 shown in phantom). The purge valve housing 22 is formed as separate component from the distribution valve housing 10. In this regard, the tubular fitting 24 must be utilized to accommodate the attachment of the purge valve housing 22 to the distribution valve housing 10. A welding operation is a typical method for attaching the two components.
The problem encountered with such an arrangement, is the inherent existence of a pronounced dead-leg. Dead-legs are areas where fluid may become trapped in a valve system when the flow of fluid in a particular branch of the system is halted. Entrapped fluid is considered a contaminant to the system. In the context of the downstream purge valve arrangement, the distance between the purge valve weir 26 to the center line of the downstream passage 16 is considered a dead-leg. The distance of the dead-leg in relation to the diameter of the dead-leg is a physical relationship which is often specified in regulations and guidelines. For example, a regulation or guideline may specify that any dead-leg must have a distance less than 6 times the diameter (referred to as the 6D rule). As such, minimization of such dead-leg distance to diameter ratio and drainage of the dead-leg is desirable.
Accordingly, there is a need in the art for an improved distribution valve and purge valve arrangement in comparison to the prior art.
In accordance with an embodiment of the present invention, there is provided a valve housing with integral downstream purge. The valve housing is provided with an integrally formed valve housing block. The valve housing is further provided with a main flow channel formed through the valve housing block. The valve housing is further provided with a distribution valve mounting surface formed upon the valve housing block. The valve housing is further provided with a distribution port formed in the valve housing block. The valve housing is further provided with an upstream distribution passage extending from the main flow channel to the distribution valve mounting surface. The valve housing is further provided with a downstream distribution passage extending from the distribution valve mounting surface and to the distribution port. The downstream distribution passage is in fluid communication with the upstream distribution passage for passage of fluid flow from the upstream distribution passage through the distribution port. The valve housing is further provided with a purge valve mounting surface formed upon the valve housing block. The valve housing is further provided with a purge port formed in the valve housing block. The valve housing is further provided with a first purge passage extending from the purge port to the purge valve mounting surface. The valve housing is further provided with a second purge passage extending from the purge valve mounting surface to the downstream distribution passage. The second purge passage is in fluid communication with the first purge passage for passage of fluid flow from the purge port through the first and second purge passages into the downstream distribution passage.
According to an embodiment of the present invention, the second purge passage is positioned relatively above the first purge passage with the second purge passage disposed between the main flow channel and the first purge passage. Further, the first purge passage is formed to decline from the purge valve mounting surface toward the purge port for allowing fluid drainage of the first purge passage towards the purge port.
According to another embodiment of the present invention, the first purge passage is positioned relatively above the second purge passage with the first purge passage disposed between the main flow channel and the second purge passage. In addition, the housing body further comprises a purge valve weir disposed between the first and second purge passages adjacent the purge valve mounting surface. The first purge passage is defined by a first purge passage inner circumference thereof, and the purge valve weir is formed tangentially relative to the first purge passage inner circumference. The first purge passage is horizontally aligned from the purge port to the purge valve weir. Further, the second purge passage is formed to relatively decline from the purge valve mounting surface towards the downstream distribution passage for allowing fluid drainage of lithe second purge passage towards the downstream distribution passage.
In addition, the distribution valve mounting surface and the purge valve mounting surface are disposed upon opposing faces of housing body. In this regard, the valve housing block may have opposing front and back lateral faces disposed longitudinally along the main flow channel. The distribution valve mounting surface is disposed upon the front lateral face, and the purge valve mounting surface is disposed upon the back lateral face. The valve housing block may further have opposing first and second lateral faces disposed transverse with the main flow channel. The purge port is formed in the first lateral face. The valve housing block may have opposing first and second lateral faces disposed transverse with the main flow channel. The purge port is formed in the first lateral face. The valve housing block may further have a bottom face with the distribution port being formed in the bottom face.
As such, based on the foregoing, the present invention mitigates the inefficiencies and limitations associated with prior art arrangements. In particular, the valve housing of the present invention is provided with the integrally formed valve housing block. Such valve housing block is commonly utilized for both the distribution valve and purge valve functions. Unlike prior art configurations which a distribution valve housing must accommodate attachment of a separately formed purge valve housing through a intermediate tubing, the present invention integrates both components into a single structure, the integrally formed valve housing block. As such, the dead-leg between the purge valve weir to the downstream passage is minimized. This is because the design avoid use of any intermediate tubing or piping to interconnect separately formed distribution land purge valve components.
Accordingly, the present invention represents a significant advance in the art.